personally it is the bored piles with cappingbeam and lagging wall. ($Y6hn+
the main reason for this collapse may be the shortage of bending moment resistance of the wall. the surrounding building is the critical origin of the large lateral force. /WE1afe_R
from the photo it can be seen that the site soil is not so bad. P]||Xbbp
measures may be : soil nailing between the piles to increase the wholly stability of the wall; nh+f,HtSt
increase the embedment (if the collapse came from overturning of the wall); prop up the wall with berms or inclined wall; or tie back from the back of the wall; mdPEF)-
meanwhile, monitoring should be carried out very carefully.